A huge mushroom cloud of dust is expected to rise over Nevada's desert in June when the Pentagon plans to detonate a gigantic 700-ton explosive -- the biggest open-air chemical blast ever at the Nevada Test Site -- as part of the research into developing weapons that can destroy deeply buried military targets, officials said yesterday.

The test, code-named "Divine Strake," will occur on June 2 about 90 miles northwest of Las Vegas in a high desert valley bounded by mountains, according to Pentagon and Energy Department officials.

"This is the largest single explosive we could imagine doing," said James A. Tegnelia, director of the Pentagon's Defense Threat Reduction Agency, which is conducting the test. ["I don't know; I can imagine quite a bit." - Han Solo]...

...The June test will detonate 700 tons of heavy ammonium nitrate-fuel oil emulsion -- creating a blast equivalent to 593 tons of TNT -- in a 36-foot-deep hole near a tunnel in the center of the Nevada Test Site, according to official reports. It aims to allow scientists to model the type of ground shock that will be created, and to weigh the effectiveness of such a weapon against its collateral impact...